Sleep terrors are episodes of screaming, intense fear, and flailing while still asleep. Also known as night terrors, sleep terrors affect almost 40 percent of children.

From the key difference between nightmares and sleep terrors to potential triggers, Sara Siddiqui, MD, clinical assistant professor in the Department of Pediatrics and pediatrician at Hassenfeld Children’s Hospital at NYU Langone and NYU Langone Huntington Medical Group, and other experts offer insight on how to navigate this type of sleep disorder.

The biggest difference between a sleep terror and nightmare is the child’s awareness. Nightmares occur during a separate stage of sleep than sleep terrors: the former happening in the second half of the night during REM sleep, and the latter tending to happen in the first third of the night during the deepest period of non-REM sleep, according to Dr. Siddiqui.

“If sleep terrors seem to be occurring at the same time every night, then I may ask the parents or caregivers to wake the child 15 to 20 minutes before the event to try and break the cycle,” says Dr. Siddiqui. “Keeping a sleep journal is helpful to track when the episodes occur.”

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